Rotary cutting tools are used to machine on workpieces. In particular, rotary cutting tools may be used to remove material from a workpiece, so as to form a workpiece to a desired size or shape or create particular features on the face of a workpiece. Generally, a rotary cutting tool is turned around its longitudinal axis while one or more cutting edges on the cutting tool are brought into contact with a workpiece so as to remove material from the workpiece. Rotary cutting tools include mill cutters such as end mill cutters and ball nose cutters, which are used in milling machines to form features such as slots, keyways, and pockets on a workpiece. Other types of cutting tools include drills, which may be used to form cylindrical holes in a workpiece, as well as mill drills, which may be used similarly to a milling machine.
The performance of a cutting tool is dependent upon the quality of its one or more cutting edges. Over time and as a result of prolonged use, the one or more cutting edges of a cutting tool may become dull as a result of prolonged physical contact between the cutting tool and workpieces. Cutting tools generally remove material from a workpiece through abrasion; the friction caused by this repeated rough contact may slowly wear away or dull the cutting tool.
As a result, cutting tools typically last for limited amounts of time before requiring replacement. The operational life of a cutting tool may be extended by employing replaceable cutting edges (for example, in the form of replaceable cutting inserts or drill bits), which allow the life of the cutting tool itself to be prolonged by using new cutting edges.
Replaceable drill bit inserts or cutting inserts are well known in the art. By way of example, U.S. Pat. No. 9,085,947 to George et al. discloses a rotary drill bit for engaging an earth strata material featuring a removable cutting insert. Similarly, U.S. Pat. No. 7,311,480 to Heule et al. discloses a drilling tool cutting insert adapted to be clamped in a rotatably driven drilling tool base body. U.S. Patent Publication No. 2007/0036622 provides a removable spade drill insert. The contents of these references are incorporated herein by reference in their entireties.
However, the one or more cutting edges on the drill bit or cutting insert wear down over time, requiring that the drill bit or cutting insert be replaced. This necessitates ongoing costs associated with purchasing and storing replacement parts as well as the logistical overhead required to manage the replacement parts. Further, time is lost each time a cutting tool needs to be shut down, either to replace the tool itself or merely the cutting edges which have degraded.
Accordingly, there is still a need for improved cutting tools in general, and more particularly for improved cutting edges, drill bits, and cutting inserts, that overcome the disadvantages, limitations, and shortcomings of known devices. For example, it is desirable to provide an improved cutting tool that provides a longer useful life. It is also desirable to provide an improved cutting tool that is less susceptible to catastrophic failure and has improved performance characteristics, including, for example, an increased penetration rate.